Clutch and controller for printing-presses.



H. H. CUTLER. ULUTOH AND CONTROLLER FOB PRINTING PBESBEB.

APPLIOATIOH FILE) APR. 18, 1904. 1,120,375.

Patented Dec. 8,1914L 4 SHEETS-SHEET I.

H. H. CUTLER.

CLUTCH AND CONTROLLER FOR PRINTING PRBSSES. uruouxon FILED Am. 18. 1904.

Patented Dec. 8,1914.

. Ina/67% H. H. CUTLER.

CLUTCH AND CONTROLLER FOR PRINTING PRESSBS.

APPLICATION IILBD APR.18, 1904.

Patented Dec. 8, 1914.

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CLUTCH AND CONTROLLER FOR PRINTING PRBSSES.

APPLICATION FILED APB..18, 1904.

Patented Dec. 8, 1914.

UNITED STATES PATENT OFFICE.

HENRY I-I. CUTLER, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMER MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

CLUTCH AND CONTROLLER FOR PRINTING-PRESSES.

Specification of Letters Patent.

Patented Dec. 8, 1914;

T 0 all whom it may concern Be it known that I, HENRY H. CUTLER, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Clutches and Controllers for Printing-Presses, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to magnetic clutch power transmitting apparatus, my object being to provide improved means whereby power may be transmitted from suitable driving mechanism to any desired driven mechanism in an efficient and economical manner.

' In accordance with my invention, I employ a magnetic clutch or accelerator, which is interposed between the driving mechanism and the driven mechanism, this clutch being constructed and arranged for operation so that the load may be readily connected with the driving motor and efficiently operated in connection therewith.

In an application filed b me August 5th, 1903, Serial No. 168,388, I have described and claimed an improved form of magnetic clutch or accelerator comprising a primary or inducing member and a secondary or induced member, one of which is ada ted to be connected with the driving mec anism and the other with the driven mechanism, whereby through the energization of the clutch the driven part may be caused to rotate at any desired speed equal to or less than that of the driving part. In this clutch I utilize the effect of induction and also the effect of frictional contact between the driving and driven members to efiect the acceleration of the driven member. Due to the peculiar and novel construction oi this clutch the energizing current when admitted to the winding of the clutch does not, as in the case of ordinary magnetic clutches, cause the driving and driven arts to be forcibly gripped and clutche together, but on the contrary the driven member is gradually accelerated in speed until eventually it is brou ht' to the full speed of the driving part i desired. This gradual acceleration is accomplished principally for two reasons:

First. Because the clutch is so constructed that considerable inductance is developed therein, so that the energizing current does not bring themagnetic field to full strength immediately, as is the case with the ordinary magnetic clutch, but causes the strength of the magnetic field to gradually mcrease until it reaches its maximum, thereby exerting a gradually increasing torque upon the driven member.

Second. Because the combined inductional and frictional effect of the driving member upon the driven member causes the driving member to exert upon the driven member a torque which is so proportioned as to cause a gradual acceleration.

The first effect above mentioned is accomplished by constructing the field magnet, which constitutes the inducing member of the clutch, so that the exciting coil will be entirely surrounded with iron, thus creating a large amount of inductance, so that when the circuit through the energizing coil is completed, the current through the energizing coil, and, consequently, the strength of the magnetic field in the inducing member is retarded; the sudden rising of ma etism to full strength, as in the case 0 ordinary magnetic clutches, resultingjn extremely sudden acceleration, is entirely obviated in my clutch, due to the employment of this construction, which produces a large amount of inductance.

With respect to the second cause of gradual acceleration above mentioned, it is a well-known fact that if the driven member of a clutch be forced against the driving member with a practically constant force, as is the case with the ordinary magnetic clutch, the driven member accelerates in an incredibly short space of time, producing the undesirable jerk and shock to the machinery which is incident to the employment of these magnetic clutches and which has rendered their use prohibitive, except in very few and exceptional instances.

In the clutch of my invention the acceleration is, due to the combined efiects of friction and induction. The frictional effeet is practically a constant force during the period of acceleration, while the inductional effect is a uniformly decreasing force during the period of acceleration; the resultant force is, therefore, a force which gradually decreases throughout the period of acceleration. Due to .the employment of a force which gradually decreases throughout the period of acceleration, I am en- 'abled to modify the law in accordance with which the ordinary magnetic clutch operates, in which the acceleration increases as the time, and with the clutch of my mvention the acceleration increases in accordance with a different law and at a much slower rate. By thus employing a clutch whose rate of acceleration is comparatively small, I am enabled to gradually accelerate the driven member of the clutch, and accord- 5 ingly Inlay apply the clutch to the dr1ving of machinery which demands such gradual. starting The clutch of my invention further lends itself to this gradual starting principally for two addditional reasons:

Third. The wearing surfaces are supplied with anti-frictional material and are arranged to run in oil, thereby permitting a large amount of slipping between the memhere of the clutch without appreciable wear.

In the ordinary magnetic clutch, any material amount of slipping between the two members will cause excessive wear and will result in the cutting of the contact faces of the clutch, thereby destroying the effectiveness of the clutch. In accordance with my invention, however, the contact faces are. specially formed so as topermit the neces? sary amount of slippage to secure the gradual acceleration.

Fourth. The elements of the clutch-are so constructed that a large amount of material may wear away, due to the slippage between the members, without destroying the effec- 4 tiveness of the device.' Polar surfaces are provided, which interpose a considerable thickness of material between the energiz-- ing winding and the contact face of the field magnet of the clutch, and, accordingly, a considerable amount of material may be worn away due to the friction, without in any manner alfecting the operation'of the clutch; likewise, the armature member of the clutch is so constructed that a considerable wearing away is permitted without in any manner. afi'ecting the operation of thedevice.

A further feature of the clutch of my 1nvention is the provision of means whereby the driving and the driven members may be' practically instantaneously separated when the circuit through the energizing cell is opened. It is a well-lmown fact thatafter the energizing current'ceases the residual e0 magnetism of the'field magnet member will serve to attract the armature member for a definite period. It is desirable in practice thatthe primary member should release the secondar member at once upon the opening 5 of-the'clrcuit through the energizing coil,

-magnetizing force is withdrawn.

'pieces and the other havin wa ers the field'magnet into a large number'of individual magnetic circuits, which aid in causing a rapid disappearance of the magnetism in the armature member when the Second. I introduce into the magnetic circuit a reluctance in the form of a small air gap, or

thin layer of non-magnetic material, or magnetic material of low permeability, so as to increase the total magnetic reluctance of the magnetic circuits. In the clutch of my invention l have found that even in the absence of this specially introduced magnetic reluctance, the residual magnetism will disappear in an extremely short time, that is, from one to six seconds. .By the addition of the magnetic reluctance as above described, ll am enabled to eliminate even this small tlme lag and to secure a practically instantaneous release. This air gap, or equivalent, need only be about one sixty-fourth of an inch thick, and therefore has a very slight efi'ect 1n decreasing .the power of the clutch. I preferably introduce this magnetic reluctance at a' point in the magnetic circuit reof the clutch of my invention I provide a back plate, upon which are mounted two rings, one having inwardly extending pole outwardly extend ng pole pieces, the po elpieces of the two rings interlacing and overlapping, the

energizing coil being located in a. channel formed by these three parts. In practice I referably providejhe special magnetic reuctance by mterposing an air. gap between the back plate and the rings carrying the pole pieces or by inter osing a thin layer of non-magnetic materia or magnetic material of low permeability between the back .plate and these rlngs. By inserting the magnetic reluctance at this locality, the desired efi'ect 1s produced without in any mannerinter'fering with the efi'ective action of the primary member upon the secondary member. s

It w ll be seen that'my invention is ecuharly applicable where-it is desired tolmpart motion from a driving mechanism toa driven mechanism, andfto providethat the driven mechanism maybe instantaneously released from-the ,driving mechanism at will. Due to the fact that the clutch of my inventlon causes a practically instantaneous release, the openlng of the. circuit throu h the energizing wm'ding causes a practicafiy instantaneous separation of the driving and the driven member's.

Isa

ism will instantly disappear when the current'is cut off from the energizing coils. This may be also accomplished as shown in Fig. 6, by placing, between the back plate 12 and the rings 14 and 15, a thin layer 23 of non-magnetic material or magnetic material of low permeability. In actual construction thisthin strip need only be made one sixty-fourth of an 1nch in thickness, and

therefore has a very slight effect in decreasing the power of the clutch. A primary member of similar construction is formed on the opposite side of the back plate 12 is secured to the peri hery of a steel disk 27,

the inner edge of wh 'ch is secured by means of bolts to a flange 28 carried upon the hub 29, rotatably mounted upon the shaft 9.

The pinion 3 is adapted to mesh with a geartwheel 30 keyed upon a shaft 31 mounted immediatel beneath theelutch in journals 32,32. lso keyed upon the shaft 31 'is a pinion 33, which is adapted to mesh with the gear teeth 26 formed on the outer perifphery of the armature 25. Mounted upo and ll is a pinion 34, which is adapted to mesh with and drive the gear wheel 36 mounted upon the shaft of the machinery to be driven. 1

In Fig. 3, the circuit arrangement and controlling apparatus for the above described deviee are shown. The contact arm 37 of the regulating resistance 38 is adapted to move over thesegments or terminals 39, 39. The contact arm 37 is connected with one side 40 of the supply circuit, the end of 1 the resistance 38 being connected by conductor 41 through the armature 42 of the motor, thence by conductor 43 to contacts 44, 44, adapted to be bridged together by the contact plate 45. The overload magnet 46' is included in series with the supp'l'y'conduetor 47, connected with the other side of the supply circuit. The shunt coil 48 of the motor is connected by conductor 49 with the contact segment 50, a resistance, 51 subdivided into sections connected with the terminals 52, being also connected with said conductor and arranged at theextremityof the segment '50. The contact arm 37 carries a brusli 53 adapted to engage the segment 50 and to sweep over the terminals 52 when the 5 contact arm is moved to its extreme 13051131011" in cutting out the resistance 38. A, second brush 54 carried by the contact ,arm 371s adapted to'initially rest up'd'n a dead contact the shaft 9 between the journals 10' minal of the winding of a solenoid or magnet 59. The circuit then extends from the opposite terminal of the winding of the solenoid 59 through the conductor 60, through the push buttons 61, the conductor 62 and the contacts 63 and 64 of the overload ma et 46 to the conductor 47. The core of t e solenoid 59 carries at its lower end the contact plate 45 and at its upper end a pin 65 adapted, when the core is attracted, to engage and move the latching lever 66, which is pivoted at 67 and which carries upon the end a hook 68 adapted to engage the end of a lever 69, pivoted at 70 and provided with a spring 71 which tends to move the end of said lever from the contact terminal 72 to the other contact 73. The contact 72 is connected by conductor 75 with the conductor 57 upon one side of the resistance 58 and the lever 69 is connected by conductor 74 with the conductor 57 upon the opposite side of said resistance, so that the lever 69 when resting upon the contact terminal 72 shunts or short circuits vcircuit. The lever 69 carries a lateral arm 76 adapted to be engaged by the contact arm 37 when moved to the initial position, whereby the movement of the contact arm to the necessary position to cut in all of the resistance 38 serves to short circuit the resistance 58, the lever 69 being held in short circuiting position by means of the latching lever 66.

In parallel with the armature 42 of the motor, a conductor 77 is provided. The circuit through said conductor being normally opened at contacts 78, 7 8, which are adapted to be bridged together by the contact plate 79 carried upon the core of the solenoid magnet 80. A resistance 81 is provided in circuit with the conductor 77. Upon the contact arm' 37 a contact bar 82 is mounted, which is insulated from the contact arm. A contact button 83 is connected by conductor 84 with one terminal of the solenoid 80, the

opposite terminal thereof being connected by conductor 85 with the conductor 43. A

contact button 86 is connected by conductor The buttons 83 and.

87 with conductor 41. V 86 are relatively. insulated, but when the contactbar 82 is moved to engage the two buttons it electrically connects thev same.

The controller arm 37 is provided with a third contact brush 88, adapted'to make contact with the two outer segments 89 and 90,

My invention is also peculiarly applicable to that class of machinery in which it is desired to operate the driven mechanism at two or more distinct speeds, as, in this case, a pair of my magnetic clutches may be em.- ployed in connection with suitable gearing for securing the different speeds and the driving mechanism may be instantaneously disconnected through the agency of one of themagnetic clutches and gradually trans-- ferred to the influence of the-other magnetic clutch in the desired manner. This feature of my invention lends itself peculiarly to the control of printing presses, turrets of battle ships, and the like, where it is desired at times to operate at a very slow speed and also to operate at a much higher normal speed. By employing a plurality of mag-. netic clutches, suitably associated, the driven mechanism may be caused to operate efliciently at any number of desired speeds.

My invention is equally applicable to that class of machinery wherein it is desired to operate the driven mechanism first in one direction and then in another, as in many classes of reciprocating machinery, such as small printing presses, planers and similar machine tools. By employing two magnetic clutches, made in accordance with my invention, and suitable gearing, the driving motor may be caused to operate the driven mechanism first in one direction and then in the other.

The above instances are cited merely to show the general applicability of my invention and are not intended to be an exhaustive enumeration of its various fields of utility.

For the purpose of fully disclosing the features of my invention, I have illustrated in the accompanying drawings several em bodiments of my invention.

In the drawings Figure 1 is an elevation of the motor and the clutch, the clutch being shown in section; Fig. 2 is a face view of the primary member of the clutch; Fig. 3 is a diagrammatic view of the circuits employed; Fig. 4 is an elevation of a modification, the clutch being shown in section; Fig. 5 is a view of a modification of the clutch; Fig. 6 is a detail view of a portion of the back plate of the modification; and, Fig. 7 is a detail view of another modification; Fig. 8 is a comparative curve illustrating the torque developed by various clutches; Fig. 9 is a diagrammatic face view of a magnetic field of my clutch.

In the structure which I have worked out as being the preferred embodiment of my 1 invention, upon the shaft 1 of the motor 2,

a pinion 3 and one armature member .4 of a double magnetic clutch are suitably keyed. The armature member 4 in the present instance is of annular form and is secured to the periphery of a steel disk 5, the inner edge of which is secured by means of bolts 6 to a flange 7, carried upon the hub 8 of the pinion 3. The primary member of the double clutch is keyed upon a second shaft 9 mounted in alinement with the shaft 1 in suitable journals 10 and 11. The primary member of the clutch is provided with two magnetic fields and each field is of the same general construction, consisting briefly of a back plate 12, formed integrally with a hub 13 keyed upon the shaft 9. To the back plate, on the side facing the armature 4 are secured a pair of rings 14 and 15, the

ring 14 carrying the inwardly extending polar projections 16 and the ring 15 carrying outwardly extending polar projections 17, the two sets of poles being arranged in overlapping positions, and held in position against the back plate 12 by bolts or screws 18. The spaces between the pole pieces are filled with non-magnetic material 19, which may be Babbitt metal or other equivalent material.

An annular channel is provided in the face of the back plate 12, and the rings 14.

and 15 when placed together form an annular channel for the reception of the annular winding of the clutch. I By this arrangement the exciting coil is entirely surrounded with iron, thus creating disappear more rapidly than would be the case if a single magnetic circuit were employed. This causes the clutch to release very rapidly when the current has been shut off from the energizing coil. However, even in a construction of this character, the time lag after the current has been cut off is from one to six seconds, and it is frequently desirable to have the clutch release instantaneously, in which case I construct my field as shown in Figs. 5, 6 and 7.

In Fig. 5 is shown an air gap 20 formed between the back plate liZ-and the rings 14 i and 15 by the interposition of small washers 21 between the rings and the back plate. These washers are held in place by the bolts 18 and are shown in the drawings .(for the purpose of illustration) greatly enlarged, as the airgap in practice need only be one sixty-fourth of an inch in thickness. By the insertion of this air gap inthi's position, a magnetic reluctance is inserted in the mag netic circuit, whereby the residual magnetfor energizing either side of the double magnetic clutch. The segment 90 is connected by conductor 91 with the winding 22 of the clutch. The segment 89 is connected by conductor 92 with one terminal 93 of a single pole overthrow, knife switch 94, which switch is connected by conductor 95 with one terminal of the winding 24 of the magnetic clutch. The opposite terminals of both windings of the clutch are connected by conductor 96 with conductor 43. The terminal 93 ofthe switch is connected by conductor 97 through terminals 98, 98, which are adapted to be bridged together by' contact plate 99, carried upon the core of the magnet-or solenoid 100, with the other terminal 102 of the switch 94. 1 One terminal of the winding of the magnet 100 is connected with conductor 97 and the opposite terminal is connected by conductor 103 through the push'buttons 104, when pressed by the operator, with the conductor 62 and thence across terminals 63, 64 of the overload switch to theopposite main 47 of the supply circuit.

The operation of the device is as follows: The parts being initially as shown in Fig. 3, when it is desired to start the motor the contact arm 37 is moved over terminals 39 and the brush 54 makes contact with the con tact segment 56. Uircuit is closed from the supply main 40 through contact arm 37, brush 54, contact segment 56, conductor 57, conductor 74, contact lever 69, terminal 72, conductor 75, through winding of the solenoid 59, conductor 60, push buttons 61, conductor 62, contacts 63, 64, through the overload magnet 46, to the opposite side 47 of the supply circuit. The solenoid 59 is thus energized and attracts its core, thereby.

bridging together contacts 44, 44, through the plate 45. The circuit for the armature of the motor is thus closed and the circuit may be traced from the main 40, contact arm 37, resistance 38, conductor 41, armature 42, conductor 43, contacts 44, 44, and

- plate to the opposite side 47 of the supply main. Circuit through the shunt field 48 is closed from contact arm 37, through brush 53, segment 50, through conductor 49, the shunt field windings 48 to conductor 43. The attraction of the core of the'armature 59 causes the pin 65 to engage and unlock the lever 66, thereby releasing lever 69 and permitting the spring 71 to-move said lever to the left, thereby opening the shunt around the resistance 58. The resistance is thus inserted in series with the solenoid 59, and serves to cut down the strength of the current to a value only suflicient to maintain the core in its raised position.

The arm 37, when moved to close the CH- cuit' through the resistance 38, also moves the brush 88 into contact with the contact segment 89, andcircuit is closed, assuming the switch 94 to be in contact with the terminal 102, and one of the push buttons 104 closed, from the main 40 through the contact arm 37, brush 88, contact segment 89, conductor 92, terminal 93, conductor 97, the winding of the solenoid 100, conductor 103, push buttons 104, conductor 62, the terminals 63, 64, through the overload magnet 46 to the opposite side 4-7 of the supply main. The winding of the solenoid 100 is thus energized and attracts its core, causing the switch 99 to make contact with the terminals 98, 98. This closes the circuit to the clutch winding 24, and circuit may then be traced from main 40, through contact arm 37, brush 88, segment 89, conductor 92, terminal 93, conductor 97, terminals 98, 98, across bridge 99 to terminal 102, through switch 94., and by conductor 95 through the winding 24 of the magnetic clutch, conductor 96 to conductor 43, and thence as previously traced to the opposite side 47 of the supply main.

The motor having been started as previously described, when the winding 24 of the magnetic clutch is energized it attracts the armature 25, and power is transmitted from the shaft 1 of the motor, through the pinion 3 and the gear wheel 30 to the intermediate shaft 31. As this shaft is revolved,

the motion is transmitted by the pinion 33 the armature 25, which, being energized by the clutch, drives the same and the shaft 9 and this shaft drives, at a greatly reduced speed, the shaft 35, through the medium of the pinion 34 and the gear wheel 36.

By the above described arrangement the machinery is driven at extremely slow speed, and may be started and stopped without stopping the motor, by pressing or releasing the push buttons 10!, which closes and opens the circuit through the clutch winding, thereby energizing or deenergizing the clutch. However, if it be desired to drive the machinery continuously at slow speed, the switch 94 is thrown in contact with the terminal 93 and circuit may be traced directly from the main 40 through the contact arm 37, brush 88, contact segment 89, conductor 92,- to terminal 93, across the switch 94 to conductor 95, through the winding 24 of the clutch, conductor 96, cbnductor 43, and thence to the opposite side 47 of thesupply circuit, as previously described. By this arrangement, it is necessary, in order tostop and start the machinery, to also stop and start the motor.

Assuming that the arm 37 has been moved so that the contact arm 82 rests upon the buttons 83 and 86, the motor is then run ning at a prearranged slow speed, also driving the machinery through the gearing as described at a slow speed, and the core of the solenoid 80 occupies the position shown in be noted likewise that the circuit-through E the solenoid 80, which was opened when the 1 contact arm 37 was in its initial position, is now closed, and the solenoid 80 is thus connected in a circuit across the terminals of the motor, that is, in a parallel or shunt circuit around the motor armature] The solenoid 80 is so adjusted that when the motor is running at the desired slow speed and below the prearranged maximum limit, thecurrent traversing the said solenoid Wlll be.

insufiicient to raise the core and close the circuit through the contacts 78, 78. When, however, the speed of the motor rises above the prearranged value, the counter electromotive force developed by the armature will be increased to such an extent as to cause an increased current through the parallel path containing the solenoid 80. This increased current flowing through the said solenoid energizes the same and the core thereof is attracted, thereby closing together the contacts 78, 78, by means of the contact plate 79. The shunt circuit around the armature robs it to an extent of the current previously flowing therethrough, and the current through the motor being thus diminished,"

the speed of the. motor will materially fall. As soon as the speed of the motor falls sutficient to cause the solenoid 80 to release its core, the said core drops by gravity and the I shaft 9, thereby, driving the machinery at contact plate 7 9 is thus moved out of contact with. the contacts 78, 78, and the parallel path 77 is thereby opened. in this manner,

during this period of operation of the motor,

the solenoid 80' automatically closes and opens the parallel path 77 to control the operation of the motor and prevent the same from rising above the prearranged speed.

' As the arm 37 is moved to cut out the resistance 38, thereby increasing the speed of the motor, the brush 88 is moved out of con- "tact with the segment 89 and in contact with the segment 90, thereby deenergizing the winding 24 and closing circuit through the winding 22. This circuit may be traced from the main 40, through the contact arm 37, brush 88f segment 90, conductor 91, through the winding 22, conductor 96, to conductor-4:3, and from'thence to the opposite side 4=7 of the supply main, as previously described. When the winding 22 is energized it attracts the armature member 4: and the power is then communicated directly from the shaft 1, through the clutch of the a greatly increased speed." When the contact arm. is movedto. cut out. all the resistance 38 from the armature circuit, the resistance 51 is inserted in the field circuit, thereby increasing the speed ,ofxthe motor.

Tn Fig. d T have showna odification of my inventiomin' which if have provided but inane-m one armature member 105, which is keyed upon the shaft 9, and two primary members of a clutch are provided. The primary member 106 is loosely mounted upon the shaft 9 and adapted to engage by gear pinion -The primary member 108 is keyed upon the shaft 1, its hub being made integral with that of the pinion 3. By this arrangement it will be seen I have reversed the position of the parts shown in Fig. 1, the clutches 105, 108 occupying the position of the armature members 4 and 25. other respects the modification is similar.

F or the purpose of illustrating the rate of acceleration of the clutch illustrated as compared with other devices, I have shown in Fig. 8 a series of comparative curves. Let it be assumed that two driven machines of difl'erent character, each requiring exactly the same amount of horse power when operteeth 107 upon its outer periphery with the ating at full speed, are provided; the first type of machine to have a very large amount of friction of repose, and the second type to have a relatively small friction of repose. The first type of machine would be well represented by a printing press, whose enor mous mass of gears, cams and levers practically absorb the entire ap died ower in friction. The second type 0 machine would be well represented bya pump forcing water into a compression tank against a heavy pressure. The power required to overcome the friction in the machinery of this pump would consequently be very small as compared to the total amount of power required to force the water into the compression tank. The rate ofacceleration which would result when using the ordinary type of friction clutch or a magnetic clutch of the ring type would be-very difi'erent in these two cases of machinery.

The first type would not start to revolve until the turning efiort v had been made at least three times as great'fno as necessary when the printing press is being driven at full speed. The curves of acceleration would then be represented by a straight line 0 A, starting'from the original be very much smaller on account of the small amount of friction of repose, and the rate of acceleration would be represented by a straight'line O B l), and thepump would consequently attain full speed in a greater'f length of time on accouht'of'being sup lied horde- 23 with a smaller amount of acceleratin necessary to start it. As soon aseit er the?" printing press or the pump has acquired full speed, their'speed curve, of coursabecomesg rad parallel to'the axis of a. 1hr following out" the speed'eurt' e of the two devices, it willfi me su e be noticed that the curves 0 A D and O B D make'a very sharp angle when they reach the full speed line. It is this sudden change in the rate of acceleration that causes the undesirable jerk on the driven machinery, the extremely rapid .rate of acceleration tending to cause the driven machinery to shoot ahead and exceed the speed of the driven machine. These two'speed curves are very similar to that of a falling body. When the body is dropped from a height its 7 speed is uniformly accelerated at the end of fectly straight line untilzthey strike the line of nstant speed. This will also be noted I each second by the force of gravity and its movement is perfectly smooth until it reaches the ground. I have also shown still another curve, 0 E G H D, which illustrates the rate of acceleration which would be theoretically obtained with a centrifugal clutch. In this device the co efiicient of friction resulting from the flying weights rubbing against the casing varies as the s uare of the velocity, which, taken together with the constantly accelerating effect of the change of speed with a constant co-efhcient of friction, would make the resulting curve represented by the equation, e23 25 Such a device will bring the driven shaft upto full speed with great abruptness and meet the line of constant speed almost at right angles, making a terrific jerk on the driven machinery.

The speed curve of the multipolar clutch as described in this application may be compared to that of a falling body, which, after having acquired considerable speed, is then greatly retarded until it alights on the ground with its speed checked entirely. In other words, the curve 0 C D, whichrepresents the accelerating curve 'of my device, strikes the line of constant speed tangentially, which means that speed curve 0 E C D possesses sufficient torque at the beginning of its acceleration to start the printing press and at the same time to accelerate it inas long a time as was required to start the pump with types of clutches which have a constant accelerating force! One of the most important features of my device, therefore, consists in the structure whereby is secured the peculiar form of the curve of acceleration, which starts tangent to the line of rest and ends tangent to the line of constant speed. i

It will be noted that a very short interval of time occurs before the magnetism-of the ring clutch builds up sufficiently to put in motion the driven shaft, "so that the curves 0 A D and-O B D, which correspond to the rate of, acceleration when using ring clutches, make every slight curve with the line of'xestIandithen become almost a perin the-curve zof acceleration resulting from the use Ofiflb centrifugal clutch. 1;: It is seen however, the ta muchalonger interest of;

the fact that the driven shaft begins to acquire motion as the driving shaft is accelerated in speed; but no motion of the driven shaft can 0( ".ur until the driving shaft has reached a sufficient speed to produce sufiicient centrifugal force to overcome the friction of repose of the driven shaft. Having once overcome this friction, the rate of acceleration is extremely rapid, increasing as the cube of the time, and finally meets the line of constant speed almost at right angles;

Referring now to curve 0 E U D, which represents the curve of acceleration produced by my multipolar clutch, it will be noticed that a time, 0 E, elapses before sufficient magnetism is developed to start the driven shaft, due, as explained in the specifications, to the large amount of self-induction possessed by this device. The curve then starts off tangentially to the line of rest and as shown by the curve the clutch acquires promptly its maximum torque. The accelerating force then drops off greatly, so that no part of the accelerating curve is ever a straight line. As the curve approaches the line of constant speed, it drops off still more sharply, and finally meets the line of constant speed almost tangentially.

In Fig. 9 is shown a diagrammatic face view of a magnetic field of my clutch. In order that the rapid disappearance of the residual magnetism in the armature member may be more fully understood, it will be assumed that magnetic flux starts from the inwardly projecting pole B and comes up vertically through the plane of the magnet member, as shown by the dots. This flux will then pass into the armature member and divide, half of it passing to the left and half to the right. The left-hand portion will then pass down into outwardly projecting pole A through the air gap 20 into the back plate 12, then, flowing in a right-hand magnetizing force continues. The moment,

however, the magnetizing, force is withdrawn, it will be seen, that these two oppositely flowing fluxes meet in opposition to each other in the'armature disk and destroy each other. They also react to a certain extenton the magnetism of the field projections'themselves; but it has been found that the magnetism of the field has a tendency to i ea-ere that two motors are provided, each one of which will operate a pump delivering water to a compression tank under heavy pressure, one of the motors being connected with the pump through the medium of a magnetic clutch of the ring type, and the other connected with a pump through the medium. clutch. Both motors having beenof my started and brought up to full speed, first start the pump by gradually admitting current to the winding ofthe ring clutch. As soon as this clutch is supplied with sumcient current, the pump will start and will then rapidly accelerate until full. speed is attained,,the curve of acceleration. being, approximately a straight line. Now,- deepergize the ring clutch and allow the pump to come to rest, then gradually admit current to the windings of the multipolar clutch until this pump starts. The speed ofthe pump will then} gradually accelerate but'will never acquire full speed, probably not reaching more ban one-half or full speed, and it will be necessary, in order to reach-full speed, to increase the amount of current flowing through ,the energizing coil. This illustrates the'efiect of the increased torque possessed by my multipolar clutch'in starting, due-tethe additional efiect of the increased current-set u in the armature,--whicho1t course falls on as the relative speed between the armature and field is reduced. For the purpose of further illustration, let. it ,be' assumed-that the two motors are connectedllp me similar way to a printing press. lit

will be found that when current is applied.-

gradually' to the ring type of clutch ,1,intil the press starts, the press-will assumefiull speed with greatrapidityin much less time proportionately than required. by the, pump, for the reason that the fr ction of reposeot a printing press is frequently three times as great as the friction of mot on, However, if the printing press is started through the medium of my multipolar clutch and the current is introduced 'intothe winding of the clutch gradual-1y until the press starts, the same will accelerate smoothly in speed and will actually acquire full speed without reuiring any more current ii ewinding of the exciting coil; Full speed L-will be acquired in this case becausethe in- Q creased efiect, due to inductionin the multivpolar 'clii h, is not as great as the efiect of introduced into friction, so that any machine used whose friction of repose is more than twice as great as its friction of rest will be brought up to full speed by my multi olar clutch, provided the same is given su cient power to start the machine and overcome its frictiofi of repose. I

It will .be seen by the arrangement of this device that the driven machinery may be. driven at an extremely slow speed and ate much higher speed by the same motor, means being also provided whereby the driven machinery, when working at an extremely slow speed, may be started or stopped from various points, without stopping or starting the motor. It will also be seen that by the use of a clutch of the character described, when the speed is changed there is no jaror shock to the machinery, due to the sudden acceleration of the speed, but that the speed increases gradually; also when one armature of the clutch is released and the other energized, the release is imme diate and one side of the clutch does not pull against the opposite side, thereby straining the parts. I V

While in the appended claims I have re*; ferred to two driving members and a driven member, rangement may members become the driven members.

be reversed and the driving instead of using a single primary member,:- 4 l contemplate using two primary memberse v adapted to inductively influence asinglesecm 2w ondary member. Moreover, the field malgnets of the two clutches, instead of being 1 formed into a unitary structure, may be physically separate and individual str'uc tures. Q

According to some phases of vmy invention I contemplate using other arrangements of the parts of my variable speed." mechanism to obtain the results that are accomplished by the structure illustrated in the drawing. It'will be noted. that I have so constructed' lrny variable speed. mechanism that no .part of the gearing or mechani- I =cal connections will bedriven 'at an ex cessive rate of speed when said mechanism 1s .producmg a high speed.

It will be understood that I use the terms high speed and low speed in the claims simply to designatetwo difierent speeds irrespective ofthe degree of .difierence in these s eeds.

Having-described my invention, w atll claim as new: and desire :to secure by LettersiPa-tent is:

1. A. magnetic-clutch having a rotatable 5 magnet member and-fa rotatable 'armature member, said-magnet member having'means to attract said armature: memberuand: pro-- 1 .vide; for gradual accelerationthereof and I also-having va reluctance in its magnetic circuitz atafipoint removed from its eoiitacting' facets .efieet instentaneous treleaseeli ited it will be-understood that this armembers provided with means to cause one of said members, the driven member, to be accelerated through the combined influence of induction and friction, and electromagnetic means for causing an instantaneous re lease of one of said members from the other when the energizing windings of the clutch are deprived of operating current. I

4-. A magnetic clutch having two rotatable members provided with means to cause one of said members, the driven member, to be accelerated through the combined influence of induction and friction, and means for introducing a magnetic reluctance in the magnet member of the clutch to assist in causing an instantaneous release of one of said members from the other when the energizing windings are deprived of operating current. l

5. A magnetic clutch havingtwo rotatable members provided with means to cause one of said members, the driven member, to be accelerated through the combined influence of induction and friction, and means for introducing a magnetic reluctance in the magnetic member of said clutch at a point removed fromthe contact face of saidmember to assist in causing an instantaneous release of one of said members from the other when the energizing windings are deprived of operating current.

6. A magnetic clutch having two rotatable members, one of said members comprising a magnet member and bein formed of a back plate, an outer ring having a plurality of inwardly extending pole pieces and an inner ring having a plurality of outwardly extending pole pieces secured to said back plate, an energizing coil, and means for introducing a magnetic reluctance between said back plate and said rings.

7. A magnetic clutch having three rotatable members and electromagnetic means 'to cause attraction between one of said members and either of the two remaining memhers and to provide for gradual acceleration of the attracted member,-said electromagnetic means also including means assisting in effecting an instantaneous release of said members when said electromagnetic means is deprived of current.

8. A ma table mem ers including. field magnets --to etic clutch having three rotacause an attraction between one of said members and either of the two remaining members and to provide for gradual acceleration of the attracted member, and means providing said magnets with a reluctance to effect an instantaneous release of said memhers when deprived of current.

9. A magnetic clutch having three rotatable members including field magnets to effect attraction between one of said members and either of the remaining members, the magnet member having means provided for gradual acceleration of the attracted member, and means providing a magnetic reluctance for the magnet memberat a point removed from its contact face for the purpose set forth.

10. A magnetic clutch'having three rotatable members provided with means to cause the driven member or members to be accelerated through the combined influence of induction and friction, and electromagnetic means to'assist in causing an instantaneous release of said members when the energizing windings are deprived of operating current.

11. A magnetic clutch having three rotatable members provided with means to cause the driven member or members to be accelerated through the combined influence of induction and friction, and means for introducing a magnetic reluctance in the magnet member to assist in causing an instantaneous release of said members when the energizing windings thereof are deprived of current.

12. A magnetic clutch having three rotatable members provided with means to cause the driven member or'members to be accelerated through the combined influence of induction and friction, means for introducing a magnetic reluctance in the magnet member of said clutch at a point removed from the contacting face of said member to tatable members and comprising field magnets for causing the attraction of either of two of said members and the third,member, said field magnets each comprising a back plate, .a ring having inwardly projecting pole pieces and a ring having outwardly projecting pole pieces secured to said back plate, an energizing coil, and means for introducing a magnetic reluctance between said back plate and said rings.

14.-A magnetic clutch having three-rotatably mounted members, meansto cause an attraction between one of said members and either of the two remaining members, and inherent means to cause a gradual acceleration of speed of a driven member when attracted to. a driving member. p

15. A magnetic clutch having three 1'0- tatably mounted members, means to cause an attraction between one of said members and either of the two remaining members, inherent means for gradually accelerating the speed of a driven member when attracted to a driving member and means for instantly releasing a driven member when an energizing winding of the clutch is deprived of current.

16. A magnetic clutch having three rotatably mounted members, comprising field -magnets to cause an attraction between one of said members and the two remaining members, and means for introducing a magnetic reluctance in the magnet member to 7 cause said members to instantlyreleasewhen the winding thereof are deprived of current, said field magnets being formed of suitable magnetic material entirely surrounding the energizing windings.

17.. A magnetic clutch having three r0- tatably mounted members, comprising field magnets to cause an attraction between one of said members and either of the two remaining members, and means for introducing a magnetic reluctance in the magnet member to cause said members to instantly release when the windings thereof are deprived of current, said field magnets being 3 formed with suitable polar surfaces interposed between the energizing windings and the contact faces of said magnets.

18. A magnetic clutch having three rotatablymounted members provided with means to cause either of said members, the driven member, to be accelerated through the combined influence of inductibn and friction, and means for instantly releasing said members when the energizing windings an of the clutch are deprived of current.

' 19. A a clutch having three rotatably mounted members, means to cause an attraction between one oi? said members and either or the two remaining members, means 4 5 for gradually accelerating the speed of one of said members, 6., the driven member, and Telectromagnetic means to cause said members to instantly release when theenergizing windings'of the clutch are deprived 5c of current.

' v 20, A'magnetic clutch having three rotatably mounted members, and comprising field magnets for causing an attractionbetween one'of said members and either of the two remaining members, inherent means for.

gradually accelerating the speed of one of said members, i. e., a driven member, when soattracted, and means for introducing magnetic reluctance in the field circuit.

to 2L'A' magnetic clutch having three rotatably mounted members, and comprising field magnets for causing an attraction between one of said members and either of the two remaining members, and means for ot graduallyaicceleratmg the speed of one of 1 machinery, of a magnetic clutch to connect ma am said members, e., a driven member, when so attracted, said field magnets each comprising a back plate, a ring having inwardly projecting pole pieces and a ring having outwardly pro ecting pole pieces, secured to-m' said back plate, and means for introducing a magnetic reluctance between said back plate and said ring.

22. The combination with a driving mechanism and a driven'mechanism, of a magnetic clutch having two relatively moving driving members and a driven member adapted to engage either of said driving members and inherent means to gradually accelerate the speed of the driven member when so engaged.

23. The combination with the driving machinery, of a magnetic clutch to connect the same with the machinery to be driven,

.said clutch having two relatively moving 8; 'driving members and a driven member the same with the machinery to be driven,

said clutch having a member adapted to be driven at a relatively slow speed, and a member adapted to be driven at a relatively high speed, a member adapted to engage r02 either of said members, and inherent means for gradually accelerating the speed of said third member.

25. The combination with the driving the same with the machinery to be driven, said clutch having a member adapted to be 'driven at a relatively slow speed, and a member adapted to be driven at a relatively high speed, and a member adapted to engage either of said members, inherent means for gradually accelerating the speed of said third member, and means to cause the same to become instantly released from, one of said members when connected with the other. 26. The combination with a motor, of a double magnetic clutch associated therewith, a rheostat, a separate electrically operated switch for" said motor and one side of said clutch, and means to control said switches and the opposite side of said clutch from the rheostat. Y

2 7. The combination with a motor, of a double magnetic clutch associated therewith, a rheostat, a solenoid switch for said motor and one side of'said clutch onntrolling the continuity offtheir circuits,'a'nd' means for controlling said switches and the other side of said clutch from said rheostat.

' of said motor and cause the operation of the other side of said clutch, and render inoperative said first side of said clutch.

30. The combination with a primary clutch member having an annular winding or windings and a lurality of circumfer entially disposed po ar surfaces, of means for lntroducing a magnetic reluctance between said polar surfaces and the support therefor, and a secondary member induc-. tively influenced by said primary member. 31. A variable speed mechanism, comprising an electric motor having a driving shaft, a d r1ven shaft, a set of gears including a 'plnion .fixed on said driving shaft, and a gear. revolubly supported on said driven shaft, an electromagnetic clutch on said driven shaft in operative relation to said gear, and a controlling device having a movab e element for varying the electrical condltions in said motor, said movable element being adapted, during part of its movement, to malntain said clutch energized.

32. An electromagnetic clutch having ro-.

tatable members, said members having contactlng faces extending substantially transversely to the axis of said members, and a.

nonqhagnetic material completely interrupting the field of said clutch and so arranged that the contacting faces of said members may make direct mechanical contact and thus eliminate interruption of the magnetic circuit between said faces.

33. In combination a driving shaft,- a

driven shaft, a magnetic clutch havin three members, one fixed to said driving s aft, a second fixed to saiddriven shaft and a third loosely mounted on said driven shaft and gearing connecting said third member to said driving shaft, said clutch being operable to first connect said driven shaft to said driving shaft through said second and third members for starting and then through said first and second members for normal operation.

34. In combination, a motor having a -driving shaft, a driven shaft, a magnetic clutch having three members, one fixed to said driving shaft, a second fixed to said driven shaft and a third loosely mounted on said driven shaft, relatively low-speed gearin connecting said thirdmember to said driving shaft and the common controller forsaid motor and said magnetic clutch operable to start said'motor and energize said clutch to connect said second and third members and further operable to connect said first and second members and acceleratethe motor.

In witness whereof, I have hereunto subscribed my name in the presence of two Witnesses.

M. R. Roonrono, W. PERRY HALM. 

